In the United States, the Sixth Amendment provides the basis for the assumption that a person accused of a crime is entitled to legal representation and if he/she does not possess the means to attain an attorney, one will be provided for him/her. Unfortunately, the reality is that the right to counsel is not uniformly implemented for indigent defendants, those who cannot afford to hire a private attorney. Indigent defendants may not receive the same access and quality of representation as those with the financial means to secure their own defense counsel. In some instances, individuals have to be eligible for appointment of counsel. Jurisdictions exercise discretion on how and when they provide these legal services to those who are deemed indigent and therefore eligible. Often, indigent defense services are underfunded and defense counsel are overburdened. Advocates for the right to counsel often lament that there is a crisis in indigent defense in the United States. Social science research on the right to counsel provision and indigent defense can play a significant role in ameliorating this crisis. In order to understand the role of empirical research in addressing the needs of the indigent defense bar, we first have to understand what research has been done to date, lessons learned from that research, and what remains to be investigated. The goal of this paper is to examine the empirical research on the types of indigent defense representation, juvenile indigent defense, and the emerging research on holistic defense. Though not an exhaustive list, these areas of research serve as a jumping off point to broaden our understanding of the "state of indigent defense" at the national level. After presenting and analyzing the literature, we examine the gaps that currently exist in our knowledge and highlight areas for future research. [ABSTRACT FROM AUTHOR]